Composite coating for electrochemical electrode and method

• US 4,981,672 A
• Filed: 07/26/1989
• Issued: 01/01/1991
• Est. Priority Date: 06/27/1983
• Status: Expired due to Term

• Current Assignee: Voltaix, LLC (Air Liquide SA)
• Original Assignee: Voltaix, Inc.
• Inventors: de Neufville, John P., Rajoria, Dalbir, Ovshinsky, Stanford R.
• Primary Examiner(s): Doll, John
• Assistant Examiner(s): Cuomo, Lori F.
• Application Number:
  US07/385,839
• Time in Patent Office: 524 Days
• Field of Search: 423/341, 423/472, 423/464, 423/301
• US Class Current: 423/464
• CPC Class Codes: H01M 10/36 Accumulators not provided for in groups H01M10/05-H01M10/34
• CPC Class Codes: H01M 2004/027 Negative electrodes
• CPC Class Codes: H01M 2300/0002 Aqueous electrolytes
• CPC Class Codes: H01M 2300/0005 Acid electrolytes
• CPC Class Codes: H01M 2300/0014 Alkaline electrolytes
• CPC Class Codes: H01M 2300/0017 Non-aqueous electrolytes
• CPC Class Codes: H01M 2300/002 Inorganic electrolyte
• CPC Class Codes: H01M 2300/0025 Organic electrolyte
• CPC Class Codes: H01M 2300/0048 Molten electrolytes used at high temperature
• CPC Class Codes: H01M 4/13 Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
• CPC Class Codes: H01M 4/242 Hydrogen storage electrodes
• CPC Class Codes: H01M 4/364 as mixtures
• CPC Class Codes: H01M 4/383 Hydrogen absorbing alloys
• CPC Class Codes: H01M 4/661 Metal or alloys, e.g. alloy coatings H01M4/669 take precedence
• CPC Class Codes: H01M 4/663 containing carbon or carbonaceous materials as conductive part, e.g. graphite, carbon fibres
• CPC Class Codes: H01M 4/669 Steels
• CPC Class Codes: H01M 50/46 Separators, membranes or diaphragms characterised by their combination with electrodes
• CPC Class Codes: H01M 6/14 Cells with non-aqueous electrolyte
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The present invention provides a coating for electrodes for use in electrochemical cells having an electrochemically active species and an electrolyte. The coating contains active species material and is selectively permeable allowing for the diffusion of the active species through the coating during operation of the cell while providing a substantially impervious barrier to the electrolyte. The coating optionally further includes a polymer layer over the active species containing coating or layer for maintaining the mechanical integrity of the active species layer.

Electrodes utilizing the coatings described herein may be used in primary and secondary cells over a wide range of operating temperatures to deliver better electrochemical performance even at room temperature.

Methods of making the coating and an apparatus for performing these methods on a continuous basis are disclosed.

A novel composition of matter is disclosed comprising lithium, silicon, and fluorine prepared by exposing lithium metal to SiF₄.

Claims

1. A compound Li_x MF_x where M is an amphoteric element and x is an integer from 1 to 6 corresponding to a valence of said amphoteric element M and the number of lithium atoms equals the number of fluorine atoms in the formula Li_x MF_x.

3. The compound of claim 1 where x=1.

4. The compound of claim 1 where x=2.

5. The compound of claim 1 where x=3.

6. The compound of claim 1 where x=4.

7. The compound of claim 1 where x=5.

8. The compound of claim 1 where x=6.

2. The compound of claim 40 wherein M is selected from the group consisting of Al, As, Ga, Ge, Mo, P, Sb, Si, Tl, W and Zn.